Generally speaking, several designs for compressed air dehumidifiers are known, and a growing demand for such dehumidifiers has been noted, especially in the vehicle field, where humid air causes severe problems.
In one type of dehumidifier a pneumatic signal from the air compressor system is used for governing the use of either one of the two containers for dehumidifying and regenerating, respectively. A typical example of this type is shown and described in the published International Patent Application WO No. 79/00642 (U.S. Pat. No. 4,331,457 granted May 25, 1982), to which reference is being made for further understanding of the present invention and in which FIG. 3 shows a control valve of the type with which the present invention is concerned.
The prior control valve design as shown therein has several drawbacks, of which an important one is the relatively long axial movement of the valve stem required to release and again lock the valve body in the form of a ball, as the valve stem must reach past the center line of the ball to safely lock it against the respective seat. This relatively long control movement not only adds to the dimension of the control mechanism extending out of the dehumidifier in an exposed position but also is a drawback for the desired function of the valve under different conditions.